Conversion studs to use 1.7 rockers on 8.1L

tbyrne · November 29, 2003

Looks like this has been out for a little while but I just came across it I'm going to investigate these some more on Monday

In stock form, Chevrolet’s workhorse “big block” is great, until someone tries to add a performance-enhancing camshaft. The non-adjustable rocker arms that lend themselves so well to low maintenance and longevity are suddenly a handicap.

For some time, Crane Cams has produced an ingenious yet simple solution – screw-in studs to convert Gen V & VI 454-502 Chevys to roller rockers. This change allows for and lends itself to any number of valve train modifications from higher lift camshafts to higher strength valve springs. Now, Crane has produced a similar stud to convert Chevrolet’s 2001-up 8.1 litre as well.

This unique high quality, low-cost rocker arm stud (part no. 99155-16) replaces the stock stud in 8.1 litre Chevys without tapping, machining or even removing the cylinder heads! The 10mm thread on the bottom end of the stud screws directly into the head while the 7/16" thread on top accepts any adjustable Chevy big block rockers such as Crane 13744-16 Energizer® or Crane 13750-16 Gold. Factory pushrod guideplates must be used to correctly align the pushrods. Heat-treated Crane pushrods (part no. 26640-16) or 3/8" diameter stockers from an 8.1 litre Chevy V-8 must be used as well.

Tom

CMNTMXR81 · November 29, 2003

Interesting! I want to know more!!

tbyrne · November 30, 2003

I should have more info on Monday.

tbyrne · December 1, 2003

I talked to the guys at Crane Cams this morning. This is a pretty easy upgrade that will allow you to use 1.7 ratio roller rockers (1.7 non-rollers come from the factory). The 8.1 comes with screw in studs so it's just a matter of removing the factor studs, cleaning out the holes, install the new studs and then bolt on a set of roller rockers (13750-16 is the part number for the Crane Golds). The Tech @ Crane quoted a 22hp improvement by switching over to the roller design. I thought that was a little high but we'll see. I should have a set here in a few days.

Tom

www.tbyrnemotorsports.com

02 2500avalanche · December 2, 2003

Can't wait Tom. I think Santa is delivering a comp cam from you guys along with the studs and rockers

Alex

CMNTMXR81 · December 2, 2003

Yes, keep us informed. If you see any major improvement, order me up a set too!

tbyrne · December 9, 2003

If your interested in the studs, rockers or a cam it would be good to place an order soon (stock orders for those manufacturers going in next week). Most of these items will be special ordered until they become popular. I was able to get a set in pretty quick and should have them in the truck in a few days. I'll drive with them until the weekend and then install the Wester's programming to see what the difference is with that.

Tom

www.tbyrnemotorsports.com

tbyrne · December 10, 2003

Well, for the guys thinking about doing this I can tell you that it will be an expensive mod in the end. Crane didn't say that the rockers wouldn't fit under the stock valvecovers So... I had to locate a set of billet aluminum spacers to get enough room under there (read - $). I'll have those in the morning.

02 2500avalanche · December 11, 2003

That sucks Tom. I still want to do this mod with the comp 1.7 magnum rockers. What rocker arms did you use? cranes? If you don't ming my asking how much are the valve cover spacers? I cam buy your place today and picked up my rotors and the rancho's You were on the phone so we didn't get to talk. You have a nice little setup down there, nice garage, the 'burban, vette, and the z28 looked right at home in there I wanted to see the HD but Im sure you were working on putting the rockers in so it wasnt around.

Alex

tbyrne · December 11, 2003

I'm going to be using Crane's Gold 1.7 ratio roller rockers. The rockers, studs and valvecover spacers are just over $700. One of the girls here had the truck out when you came by yestereday. I'll probably finish the conversion later today.